ST350ZEVE

Call me crazy, but I just purchased a new 350Z back in February. I have about 3000 miles on the car. Changed the oil at 1200 miles before which I did not rev past 4000 RPM as instructed. Every now and then when I shift from 1st to 2nd and 2nd to 3rd, and in some cases drop below 2500 RPM (in traffic of course), when I accelerate I hear a distinct knocking sound which eventually disappears after 3000 RPM and above. It's sporadic in that it does not happen consitantly, but It does happen - it almost sounds like I could have water in my gas but I know that's not it becuase then it would be a persistant sound. It's driving me effing nuts and I don't want to seem crazy when I go to the dealer and am unable to replicate the sound - becuase it does not happen all the time. Has anyone else had this problem? Or am I being nuts and this is, in fact, a normal sound for accelerating at a lower than normal RPM?

Any feedback would be appreciated -

Thanks!

03BrickyardZ

Knocking is nooooo good. Are you running 91 octane? (versus 93 octane) Is it generally when the car is warm or cold? Im assuming this is at WOT. Are you getting a CEL?

yousa thinkin yousa engine gonna die?

thanh27

iTrader: (12)

Why did you change the oil at 1200 miles? I thought the first oil change was 3750 or 3 months?

ST350ZEVE

Using 93 - it's very faint knocking that occurs at around 2500 RPM and not WOT, maybe half way in some cases. I don't hear it often because I am usually not at that low an RPM - but regardless, faint or not, it's there.

Not sure what a CEL is

ST350ZEVE

Engine is warm

ezramoore

CEL = Check Engine Light

ST350ZEVE

oh i got it - no CEL either (gotta brush up on my acronyms)

aren21

iTrader: (3)

My car does exactly what youre talking about. Yes its knocking, even though it really shouldnt. Do a search on it, and youll find out that even though some people took it to the dealer and retarted the timing, it still didnt help. People have had mixed results with the NGK 1 step colder plugs, but other than that, theres not much to do about it. The problem is only on the damn 06 cars too. Maybe thats why for 07 nissan put dual knock sensors on the vq35HR...

ezramoore

can you replicate the issue semi reliably? the dealer is your friend if you can. I'd say its pretty difficult for people to diagnose without hearing it. To make absolutely sure its not your fuel go to a different station next time you fill up, I recommend Cheveron, and of course fill it with 91-93 octane. I know my post hasn't been a ton of help, I don't know too much about fuel with relation to noises, or knocking in general, but I do know its a process of elimination. good luck, don't forget to tell us what it was/how you solved it once you find out.

ST350ZEVE

Nice to know i am not alone - however, should i be worried or is it no big deal? It's funny how it is not consistant. And if I just had a tendency to shift at higher RPMs, I probably would never have noticed it.

aren21

iTrader: (3)

good point on the fuel thing. I noticed it does it MUCH less with chevron fuel. It still knocks, but not as bad...try chevrons 91 (or if youre lucky enough to have 93 where you live, go for it)

ST350ZEVE

Thanks guys! Actually - i have been to different places. Shell and Sunoco with same result. Have not tried Cheveron, though. 93 is available at Sunoco. Thanks for the suggestion and will do.

ezramoore

I would NOT buy gas at shell. They had to pay over $500 for each car (2) in our family because their fuel screwed our fuel injection systems.

Blu_Blur

iTrader: (1)

LOL!

Bevo

Some people prefer to change it right after break-in period to get rid of the metal shaving

ezramoore

From what I've read, Chev is the best fuel in the nation. Its the only fuel we use in my girlfriends Z

cavallino33

I have the same issue with knocking /pinging. I used Shell 91, tried Chevron it did it too. I use 76's 100 octane but it still does it though much less frequently. I took it to the dealer and neither they nor I could replicate it. It's kind of weird I'll drive it one day and it'll be fine than the next time it'll do it a bunch. I don't feel anything from it just hear it very faintly.

aren21

iTrader: (3)

yea its just annoying when I drive with the windows down to hear the sweet music from the tailpipes, and i hear freaking knock...I think a louder exhaust should "solve" the problem lol.

CLMZ

Do you hear a knock (as in a rod) or a ping (as in fuel) ??

ST350ZEVE

What a difference a day makes. Funny that you ask, becuase I think it's related to neither feul or engine now. I think a true knock would be louder, and it's not a ping - it's something inbetween. I think it's the clutch plates. Is that possible? I may have developed some bad habbits over the years driving sub par performance vehicles. Rolling through stop signs in 2nd, downshifting without double-clutching, or even downshifting unnecessarily. I noticed yesterday that sometimes my clutch makes a funny sound when I engage it to rapidly in a down shift (going slow, but still probably not a good thing to do). The sound is similar to the "knocking". And in fact, soon thereafter is when I notice the knocking upon acceleration and eventually it stops happening until i repeat the cycle. SO - I have since modified my habbit and have been shifting smoother and probably how I should have been the whole time. And maybe being a high performance car, it lets you know when you are EFFING up? Because now, I have not been hearing it. I basically have been shifting at higher RPMs (3.5 - 4) and not doing stupid stuff and being lazy rolling through stop signs in 2nd - harsh down shifting, etc - and I see an improvement.

aren21 - you most likely are driving the car as it should be driven unlike myself! However, if what I mentioned above helps - let me know.

Thanks everyone for the feedback - I will see how it goes the next couple of days and update if necessary.